Located in the Turkmenistan desert is The Darvaza Flaming Gas Crater, also called The Doorway to Hell. This crater was created sometime in the 50s when the Soviets were prospecting for natural gas in this area and the equipment apparently fell in and exploded, and it's been burning non-stop since then.
Link goes to gallery of what can be called both a natural disaster and a natural wonder simultaneusly.
Sources: Multiple. Neatorama, Fogonazos, and English Russia all reported on this at seemingly the same time. This here is the photographer's webpage with his pics, but it seems to be down now.